A pressure variable thermal adaptive microclimate surface is provided. The microclimate surface may be a pad, pillow, mattress or the like. The microclimate surface is especially suitable for providing optimal heating and/or cooling of a person. The device has a pressure variable thermal adaptation function which is embodied in three possible system types. In all three types the pressure thermal adaptivity is produced by the partial compression of the sculpted resilient foam cushioning which (while generally maintaining its skin protecting resilience) reduces the foam's insulation properties (by collapsing the internal air bubbles) and thereby increasing its thermal conductivity proportionally where pressure is applied. Because the location where the greatest pressure is applied is also the area which needs the greatest thermal therapy, the device optimizes the effectiveness of the thermal delivery system. For example, pressure ulcers can form in hospitalized people due to localized persistent pressure and high temperatures under bony prominences such as the sacral (tailbone) region. Healthcare mattresses are made using fluid impervious coated covers to enhance disinfectability. These covers, however also almost completely eliminate the flow of air necessary for our skin's temperature management system, which relies on evaporative cooling from our sweat glands. Without constant airflow these parts of the body become warmer and the un-evaporated perspiration can further reduce skin integrity due to maceration, leading to potential damage such as infections and pressure ulcers. In the current state of the art, liquid or air circulating channels collapse proportionally with applied pressure thereby reducing or eliminating the thermal transfer where it is most needed. With the greater thermal conductivity the invention provides, cooling or heating from the system is efficiently directed to the areas with higher pressure which need the thermal therapy most.
The heating or cooling is provided through a heating or cooling delivery system located in the sculpted polyurethane foam microclimate surface. The microclimate surface has a plurality of independently moving pillars which is optimal in reducing pressure ulcers on the skin of a person caused by the person spending extended periods of time on a typical surface, such as a hospital mattress. The heating or cooling delivery system may be provided through three possible configurations: I) Fluid (cooled or heated) is circulated through a tubing matrix which is placed within the sculpted foam surface using a connected thermoelectric device. The electrically powered device consists of one or more thermoelectric cells, a power supply, a pump, a heat exchanger, a fan, electronic thermostatic controller, and a control panel with a user interface (temperature readout, power on/off, set temp, it may or may not have a timer function); II) Fluid (cooled or warmed) is circulated through a tubing matrix which is placed within the sculpted foam surface using a radiator device. The electrically powered radiator device may be integrated within the mattress or in a separate tubing connected component. The radiator device consists of a pump, a heat exchanger with or without fan, and a user interface; III) The third embodiment incorporates a plurality of small thermoelectric cells which are connected by wiring and inserted into chambers cut into the sculpted foam. These thermoelectric cells are placed so that the thermal therapy side (cooling in this instance) come in closer contact to the patient's body presenting the greatest pressure to the surface. A circulating system of fluid (gas or liquid) is used to draw heat away from the warm side of the thermoelectric cells. This system incorporates a heat exchanger, fluid pump or blower, a controller and a user interface. All three systems may also incorporate one or more separate sensors which can be placed to detect the temperature in localized areas to optimize the setting.
Pressure ulcers, also known as decubitus ulcers or bedsores, are lesions caused by unrelieved pressure on soft tissues overlying a bony prominence which reduces or completely obstructs the blood flow to the superficial tissues. According to the Agency for Healthcare Research and Quality (AHRQ), the occurrence of pressure ulcers in patients has risen 63% over the last ten years. Accordingly, attempts to maximize temperature exchange and reduce pressure while a patient is on a mattress have been made over the years.
For example, U.S. Pat. No. 6,874,185 to Phillips et al discloses a foam core cushion mattress assembly having semi-independent foam pillars on the upper surface of the mattress. The mattress may be unitary, or comprise multiple cushioning components, possibly base, body support and foot cushions. The body support cushion is constructed from a flat, rectangular solid, foam element whose upper surface is cut into an array of rectangular solid pillars, preferably by a hot wire cutting method. The array of rectangular solid pillars is grouped into a central array comprising pillars with generally square top surfaces and edge rows of rectangular solid pillars having rectangular top surfaces. The depth of the hot wire cuts into the surface of the body support cushion is preferably approximately one-half the overall thickness of the body support cushion or approximately three fourths of the length of the shortest face of the pillar. A zippered fabric cover removeably envelops the assembled cushioning components. The resultant structure defines a plurality of semi-independently compressible pillars that support a reclining, or supine patient. The pillars may also be cut into the top and bottom surfaces of the cushion for enhanced pressure relieving effects. Methods of manufacture, and treatment and alleviation of decubitus ulcer formation are also presented.
U.S. Pat. No. 6,375,674 to Carson discloses a medical pad having a thermal exchange layer capable of absorbing and/or releasing heat to a patient and an adhesive surface disposed on a skin-contacting side of the thermal exchange layer for adhering the pad to the skin of the patient. The thermal exchange layer may comprise a fluid containing layer for containing a thermal exchange fluid capable of absorbing thermal energy from and/or releasing thermal energy to the patient. The pad may also include a conformable, thermally conductive layer between the adhesive surface and the fluid containing layer and an insulating layer on the non-skin contacting side of the fluid containing layer. In some arrangements, transverse members or dimples on insulating base member are provided to define tortuous fluid passageways in fluid containing layer. A fluid circulating system including a pump connected downstream from a fluid outlet and a fluid reservoir connected upstream from a fluid inlet may be employed to circulate the fluid though the fluid containing layer. The fluid is drawn from a reservoir into the fluid containing layer through the inlet and out of the fluid containing layer through the outlet under negative pressure by the pump. When the pad is adhered by the adhesive surface to the skin of the patient, thermal energy is exchangeable between the patient and the fluid circulated within the fluid containing layer to cool and/or warm the patient.
U.S. Pat. No. 5,653,741 to Grant discloses a flexible pad capable of selectably heating or cooling an animal or human body part. The pad is formed of two planar surfaces having at least two side portions disposed between said planar surfaces that are made of a mesh material for air circulation within the pad. One planar surface is made of thermal conductive material having a plurality of thermoelectric modules bonded to the conductive material. The thermoelectric modules transfer heat to or away from the conductive material. A heat sink is attached to the opposing side of each modules for dissipating heat from the conductive material during the cooling process. A rheostat has a reversing switch for changing polarity of the rheostat to either transfer heat to the thermoelectric modules and to the planar surface, or from the thermoelectric module to the heat sink.
Further, U.S. Pat. No. 5,564,142 to Liu discloses an air mattress having a plurality of symbiotic sacs juxtapositionally transversely secured in a mattress envelope, having a plurality of primary and secondary symbiotic sacs alternatively pulsated in the envelope for continuously changing the pressurized areas of a bed-ridden patient for preventing pressure sores such as bed sore or decubitus ulcer, with each symbiotic sac consisting of an upper pulsating sac portion alternatively inflated and deflated and a lower static sac portion constantly inflated to maintain at least a partial fluid pressure in each symbiotic sac for continuously cushioning the patient even when a power failure is caused or bed transfer is required, and having a plurality of tertiary symbiotic sacs constantly inflated for cushioning a patient head portion, with each symbiotic sac independently secured in the mattress envelope whereby upon breaking of any one sac, only an individual broken sac should be replaced with a new one without abandoning the whole mattress.
However, these patents fail to describe a pressure variable thermal adaptive microclimate surface and thermoelectric cells for a microclimate surface which efficiently reduces the occurrence of pressure ulcers. Further, these patents fail to describe a pressure variable thermal adaptive microclimate surface and thermoelectric cells for a microclimate surface which efficiently exchanges heat and increases comfort.